Diaphragm chuck



June l5, 1954 P. A. GROBEY 2,681,229 DIAPHRAGM cHucK 1 Filed Feb. 4. 1952 Patented June 15, `1954 assiglnorf to Bryant Chuckingl Grinder: Gbmpanyi'.. Springe field, Vt., a corporation oti'Yermontf.

Application Fbruaryf4', 1952, hSerial No. 269,855Y

This invention relates'to chucks,- andlmorepar,

ticularly `for `holding' round tubular partslfor` particularly grinding, andha's:

ternal machining, for: an object to insure thenhighestaccuracy` in roundness` of work and in concentricity between4 thef outside surface and thebore For` a,4 complete understanding of this:` inven'- tion, reference may be. had totheaccompanying drawings inpwhich.A

Figuren isazcentral longitudinal sectional .viewi throughl a'zclosed` chuck..;embodyingiithesinvention, and includingvv adjacent. parts of the; spindle;v to` which` the chuckgis fixed;

Figurezzisa detail. sectional view on.1ine\2,2 I of.Figure l.

Figure :3 isv a= fragmentary rightihand or :front end I. elevation of fthe. parts shownx in Figure, 1;

Figure 4 is a viewsimilarito aportionlof` Figure l, but showing the chuck about to be opened or just-closed.'

Referring :tothe drawings, at. I is indicated a rotary work spindle having at its forward end a noseto` which the chuck may-*be attached; Asv

the welly known standard type. having a` central tubular extension` 2v4 provided withla' taperedwall 3: The chuck" comL prises a body 4 having a central recessed portion 5 which iits over the extension 2 and an annular rear face 6 which abuts against the end face of the spindle nose. This body may be secured to the spindle as by the screws 1.

The chuck body comprises a tubular portion 9 which extends forwardly in coaxial alinement with the spindle, and has at its forward end an enlarged diameter portion I to which is secured, as by bolts II, the outer marginal portion of a diaphragm I2. This diaphragm, as shown,

shown. this nose is ofA tapers in thickness, its thicker portion being adjacent to its outer margin, and it is conical in shape with its apex projecting away from the spindle I. Through this apex is provided a hole I4 normally of suiiiciently small size to grip a tubular work piece W which may be placed therein with its central portion free for machining operations, such, for example, as grinding. Between the hole I4 and the holes for the bolts Il this diaphragm may be imperforate. As shown this work piece is the external ring of a ball bearing.

Positioned rearwardly of the diaphragm is a sleeve I having a reduced diameter forward tubular portion I6 enveloping a work ejector plunger I1 and which is of a diameter to engage against the back face of the diaphragm nearer to the spindle adjacent to the central opening 5;; Claims. (Cl. 2795-1022 within which the work. pieceA W is positioned.

Byfpressing" this-member I 5` against the 'rearfface' ofitheidiaphragm, the diaphragm may be: dis tortedandthe hole for the work piece stretched-` suhcientlyfor the-work thatit "can rberemoved I and .replaced `by anotherwork" pieceato `be machined on its inner face.A

Thisstretching or expanding ofthe hole or` bore.;

isfof ve1'y-srnalla1nount but `it is suiiicient I to re-Y lease the-work piece. The holein the diaphragm when the-diaphragm is innormalunstrained icon ditionisonl'y a'ifew 1/10000 of an inchsmallertharnv theoutside-diameter of the work piece to be.,`

machined;

The/'work ejector I 'l has its end portion-slight:- I size of theV hole-1 through the diaphragm and isvinxpositioni to enn -I ly-l smaller` than; the` normal gage the rearfface of theiwork piece and eject it when f the ihole has been .stretched suiiiciently.

to-free:theworlr'piecetherefrom. This ejector,-

I:'l' is lnormallyl pressed toward ej eatingV position. by: a: springs 20 housedthereby and which lreacts@` between its recessed end face 2| and thebase.22.1 off thersockettin-aguide member 23S whichis secureditotheibodyrfl as by screws 2'4 Whichpasssy The member I5 is connected through two or more actuating rods 28 secured to an outwardly extending ange 21 thereof by screws 30, to a. sleeve 29. These rods 28 are threaded into the sleeve '29 which is slidably guided for axial motion within the central bore 3l of the spindle. The sleeve 29 may be connected to an actuating sleeve 32 as by being threaded thereto, this sleeve 32 extending through the length of the spindle and being accessible for axial motion from its opposite end where it may be actuated by any suitable means well known in the art. When the member l5 is moved to engage and stretch the central portion of the diaphragm, the ejector Il is allowed to be projected to engage and eject the work as soon as it has been freed from the diaphragm by enlargement of the hole I4, while retraction of the member I5, which allows the diaphragm to return to normal work-gripping positions, causes the rear face of the Ilange 21 to engage a shoulder 35 on the ejector I1 and pull this ejector away from the diaphragm.

From the foregoing description of an embodiment of this invention it should be evident to those skilled in the art that various changes and modifications may be made without departing from its spirit or scope.

piece to be'releasecl,` so- I claim:

1. A chuck comprising, a tubular body for securement coaxially to a spindle, a diaphragm secured adjacent to its margin to said body and having a hole coaxial with said body of a normal size to grip a work piece inserted therein, and means normally supported by said body and engageable with a face of said diaphragm adjacent to said'hole and movable to deflect said diaphragm lengthwise of the axis of said body and increasing the diameter of said hole sumciently to free such work piece. j

2. A chuck as described in claim 1, in which the diaphragm is conical and faces outwardly with respect to said spindle, and said deflecting means engages the concave face of said diaphragm.

3. A chuck comprising a tubular axial securement to one end of a hollow spindle, a conical diaphragm secured about its outer margin coaxially to said body and with its apex extending outwardly irom said body away from said spindle, said apex having a hole therethrough normally of a size to grip a work piece therein, a guide member secured coaxially in said body, a work ejector slidably guided by said guide member and having an outer end positioned to ene gage the inner end nearer to said spindle of a work piece in said hole, a tubular release member enveloping said ejector and having its outer end positioned to engage on the inner face ofhsaid diaphragm nearer to said Spindle adjacent to said hole, a member extending, through said spindle and secured to said release member and by axial motion of which said release member may be pressed against said diaphragm and said diaphragm forced outwardly away from said spindle adjacent to said hole to enlarge said hole and free a work piece therein, and a spring reacting between said guide member and ejector for pushing said ejector against and ejecting the work from said hole when said hole has been so enlarged.

4. A chuck comprising a tubular body for coaxial securement to an end of a hollow spindle, a conical diaphragm secured about its outer margin coaxially to said body and with its apex exbody for co-V tending outwardly from said body, said apex having a hole therethrough normally o1 a size to grip a work piece therein, a guide member secured coaxially in said body, a work ejector slidably guided by said guide member and having an outer end positioned to engage the inner end of a work piece in said hole, a tubular release member enveloping said ejector and having its outer end positioned to engage on the inner face of said diaphragm toward said spindle adjacent to'said hole, a member extending Vthrough said spindle and secured to said release member and by motion ci which axially of said spindle said release member may be pressed against said diaphragm and said diaphragm forced outwardly Aadjacent to said hole to enlarge said hole and Afree a work piece therein, and a spring reacting between said guide member and ejector for pushing said ejector against and electing the work from said hole when said hole has been so enlarged, said release member and ejector having parts cooperating to withdraw said ejector by withdrawal o-i said release member.

5. A chuck comprising a tubular body for securement to an end of a spindle, a conical diaphragm tapering in thickness between its margin and central portion,'being thickeradjacent to said margin, said diaphragm being secured adjacent to its margin to said body with its apex presentedV outwardly from said spindle and having a work piece receiving hole therethrough at its apex, and means engageable against the inner face of said diaphragm adjacent to said hole and actuable to force the central portion of said diaphragm axially of said body outwardly away.

from said spindle to thereby temporarily enlarge said hole to facilitate placing and removal of a work piece with respect thereto.

References cited in the me of this patent UNITED STATES PATENTS Number Name Date 1,941,025 Stein Dec. 26, 1933 2,334,045 Tinnerman Nov. 9, 1943 2,366,114 Kost Dec. 26,1944V 

